State REMOVES Cyanobacteria Lake Warning for Arlington Mill Pond in Salem, New Hampshire

Concord, NH – The New Hampshire Department of Environmental Services (DES) has REMOVED a cyanobacteria lake warning issued for Arlington Mill Pond on 8/17/2018. Samples were collected at various shorelines around the waterbody; with conditions ranging from a few thousand cells/ml to millions of cells/ml. The state threshold for a warning or advisory is 70,000 cells/ml of cyanobacteria in NH lake water. Weekly to bi-weekly sampling was collected since the advisory was first issued. The cyanobacteria were identified as Microcystis and Woronichinia. Globs of blue-green scums were sporadic around the shorelines of the lake. Samples collected on October 22, 2018 showed that the bloom had dissipated. There were only 500 cells/ml of Microcystis in the most recent samples collected. The water has been drawn down and conditions have changed since the bloom was reported. Please continue to monitor your individual shoreline for changing conditions.

Cyanobacteria are natural components of water bodies worldwide, but blooms and surface scums may form when excess nutrients are available to the water. Some cyanobacteria produce toxins that are stored within the cells that can be released upon cell death. Toxins can cause both acute and chronic health effects that range in severity. Acute health effects include irritation of skin and mucous membranes, tingling, numbness, nausea, vomiting, seizures and diarrhea. Chronic effects include liver and central nervous system damage.

NHDES advises lake users to avoid contact with the water in areas experiencing elevated cyanobacteria cell conditions typically where lake water has a surface scum, green streaks or blue-green flecks aggregating along the shore. NHDES also advises pet owners to keep their pets out of any waters that have a cyanobacteria bloom.

NHDES routinely monitors public beaches and public waters of the state for cyanobacteria. Once a cyanobacteria lake warning or beach advisory has been issued, NHDES returns to affected waterbodies on a weekly basis until the cyanobacteria standards are again met.

The warning went into effect on August 17, 2018, and was removed on October 22, 2018.

If you notice anything resembling cyanobacteria, please refrain from wading, swimming, or drinking the water. Keep all pets out of the water and contact NHDES immediately. Please call NHDES to report a cyanobacteria bloom at (603) 848-8094.